1. Field of the Invention
The present invention relates to an address generating method in a network, and in particular to a method of automatically generating node addresses and subnetwork addresses in a ring network.
2. Description of the Related Art
TCP/IP (transmission control protocol/internet protocol) is a suite of several networking protocols which is used for most UNIX implementations as well known. The TCP/IP protocol suite was developed as part of the ARPAnet project, which was a predecessor to many of the subnetworks as well as the Internet. Since an IP address consisting of a network address and a host (or node) address is a unique address assigned to a node or host on the Internet, the network address is assigned by the Internet Assigned Numbers Authority (IANA) in order to ensure the uniqueness in the world.
On the other hand, in a network to which a unique network address has been assigned, unique addresses within the network should be assigned to the nodes and the subnetworks forming the network, respectively. There have been proposed several conventional techniques relating to such address assignments as described hereinafter.
An automatic administration system for a loop network is disclosed in Japanese Patent Unexamined Publication No. 5-167595. A network administration station detects the state of a selected node and the respective MAC addresses of upstream and downstream nodes of the selected node starting from a predetermined node while sequentially selecting the nodes of the loop network until the MAC addresses and the states of all the nodes are obtained. Based on the relation of the MAC addresses and the states of all the nodes, the network administration station automatically generates a configuration information table containing the obtained data and updates the configuration information table when the network configuration is changed.
A bus adapter having an address conversion function is disclosed in Japanese Patent Unexamined Publication Nos. 63-93235 and 63-138831. Receiving a frame from a bus or ring network, the bus adapter automatically generates an address pair of node address and segment address based on the destination node address and the source node address included in the received frame. The address pair is registered into an address transform table whose size is variable according to the system arrangement. More specifically, the bus adapter is comprised of a ring interface permitting the connection of the ring network, a bus interface permitting the connection of the bus network, and a table memory storing one of n address transform tables having different sizes. When the address transform table in use has little available space, the address transform table in use is replaced with another size address transform table which is the smallest-size table among the larger-size tables than the in-use address transform table.
However, the above-mentioned conventional techniques are directed to address detection and address transform in order to cope with network system changes. There are neither description nor suggestion regarding an address assignment method for generating and assigning unique addresses to nodes and subnetworks. Although it is possible to manually assign the addresses to them in a small network, the larger size of a network results in the increased number of addresses to be assigned to the nodes and the subnetworks. Therefore, it is impossible in practice to manually assign unique addresses to them without error in a large-size network.